Corrugated fin and heat exchanger including the same

ABSTRACT

A corrugated fin has flat plate sections each having a pair of lateral sides facing each other and a pair of end sides facing each other, and joining sections connecting with lateral sides of the flat plate sections. The flat plate sections and joining sections are alternately formed into a corrugated shape by bending. The joining section has an even surface joined to a tube through which a heat exchange medium flows, while the flat plate section includes a recess or protrusions in arbitrary sections taken along two directions including a direction in which the lateral sides are arranged and a direction in which the end sides are arranged, respectively.

TECHNICAL FIELD

The present invention relates to a corrugated fin for dissipating heatof a heat exchange medium in a heat exchanger such as a radiator, an oilcooler or an after-cooler. The invention also relates to the heatexchanger including the corrugated fin.

BACKGROUND ART

In an engine room of a work vehicle such as a hydraulic excavator or abulldozer, an engine, a radiator, a cooling fan and others are placed ina predetermined pattern of locations. When driven, the cooling fancauses a flow of cooling air which passes through the radiator, therebycooling engine cooling water circulating between the engine and theradiator.

The radiator is constructed mainly of a top tank, a bottom tank, aplurality of tubes and fins.

The top tank and the bottom tank are coupled through the plurality oftubes arranged at predetermined intervals. Thus, the engine coolingwater coining from the engine is once stored in the top tank, thenpasses through the plurality of tubes to be stored in the bottom tank,and is then returned to the engine.

The fins are each disposed between the adjacent tubes and joined to thetubes by joining means such as brazing.

As an example of the above-described fin, there is a corrugated finhaving flat plate sections and joining sections that are alternatelyformed into a corrugated shape by bending (refer to, for example, patentdocuments 1, 2 and 3). The flat plate sections of such a corrugated fineach has a pair of lateral sides facing each other and a pair of endsides facing each other, while the joining sections each connect withthe lateral sides of the flat plate sections.

RELATED ART DOCUMENTS Patent Documents

Patent Document 1: Japanese Patent Unexamined Publication No.2007-232246

Patent Document 2: Japanese Patent Unexamined Publication No.2002-228379

Patent Document 3: Japanese Patent Unexamined Publication No. H09-155487

The corrugated fin is manufactured, for example, by undergoing agrooving process and a corrugating process.

The grooving process is a process of forming a plurality of grooves on asurface of a bandlike sheet by passing the bandlike sheet uncoiled froma sheet coil between a pair of grooving rollers or by press workingusing a press machine.

In the corrugating process, the bandlike sheet which has undergone thegrooving process is passed through a pair of corrugating rollers forbending, whereby the flat plate sections and the joining sections form acorrugated shape in an alternating sequence.

Examples of the grooves formed in the bandlike sheet in the groovingprocess include grooves extending in a direction in which the pair oflateral sides of the flat plate section are arranged and groovesextending in a direction in which the pair of end sides of the flatplate section are arranged.

Providing the flat plate section with the grooves extending in thedirection in which the pair of lateral sides are arranged can increase asection modulus of a section taken along the direction in which the pairof end sides are arranged. Accordingly the flat plate section can haveincreased rigidity with respect to such a bending action as to bring thepair of lateral sides close to each other. However, in this case, asection taken along the direction in which the pair of lateral sides arearranged cannot have an increased section modulus, so that the flatplate section cannot have increased rigidity with respect to such abending action as to bring the pair of end sides close to each other.

Providing the flat plate section with the grooves extending in thedirection in which the pair of end sides are arranged can increase asection modulus of a section taken along the direction in which the pairof lateral sides are arranged. Accordingly the flat plate section canhave increased rigidity with respect to such the bending action as tobring the pair of end sides close to each other. However, in this case,a section taken along the direction in which the pair of end sides arearranged cannot have an increased section modulus, so that the flatplate section cannot have increased rigidity with respect to such thebending action as to bring the pair of lateral sides close to eachother.

Therefore, during the production of the conventional corrugated fins or,more specifically, in the corrugating process, bending can possiblyoccur at an unexpected place, thereby problematically increasing adimensional error.

For this reason, the dimensional errors of the corrugated finsaccumulate when a radiator core is assembled by alternately stacking thecorrugated fins and the tubes, which in turn may warp the radiator core,leaving a problem that product accuracy is difficult to improve.Correcting the dimensional error of the corrugated fin requires extratime and effort, while assembling such that the dimensional errors ofthe corrugated fins offset one another requires a high skill In anycase, the production problematically becomes difficult.

SUMMARY OF THE INVENTION Problems to be Solved by the Invention

In view of the problems mentioned above, the present invention aims toprovide a corrugated fin capable of reliably preventing bending at anunexpected place during production, thereby improving product accuracyand facilitating the production. The invention also aims to provide aheat exchanger including this corrugated fin.

Means for Solving the Problems

To achieve the above object, a corrugated fin for a heat exchangeraccording to a first aspect of the present invention comprises a flatplate section and a joining section which are alternately formed into acorrugated shape by bending, said flat plate section having a pair oflateral sides facing each other and a pair of end sides facing eachother, said joining section connecting with a lateral side of the pairof lateral sides of the flat plate section,

wherein said joining section has an even surface joined to a tubethrough which a heat exchange medium is circulated and

wherein said flat plate section has at least one recess or protrusion inan arbitrary section taken in two directions, the two directions being adirection in which the pair of lateral sides are arranged and adirection in which the pair of end sides are arranged.

According to a second aspect of the invention that is based on the firstaspect, it is preferable that the even surface of the joining section isformed into a plane surface.

According to a third aspect of the invention that is based on the firstaspect, it is preferable that the even surface of the joining section isformed into a curved surface.

According to a fourth aspect of the invention that is based on thefirst., second or third aspect, it is preferable that two or morerecesses or protrusions are provided.

A heat exchanger according to a fifth aspect of the invention includesthe corrugated fin of the first, second, third or fourth aspect.

Advantages of the Invention

In the corrugated fin of the first aspect of the invention, the flatplate section is provided with at least one recess or protrusion in thearbitrary section taken in the two directions, that is, the direction inwhich the pair of lateral sides are arranged and the direction in whichthe pair of end sides are arranged. Accordingly, the section taken alongthe direction in which the pair of end sides are arranged and thesection taken along the direction in which the pair of lateral sides arearranged can have increased section moduli, respectively. For thisreason, the flat plate section can have increased rigidity with respectto such a bending action as to bring the pair of lateral sides close toeach other as well as with respect to such a bending action as to bringthe pair of end sides close to each other.

The joining section is not provided with any recess or protrusion suchas provided in the flat plate section. This allows a large difference inrigidity between the flat plate section and the joining section, thusenabling easy and reliable bending at a boundary between the flat platesection and the joining section.

In the corrugated fin of the first aspect of the invention, bending atan unexpected place can be prevented without fail during production ofthe corrugated fin, whereby the corrugated fin can have a reduceddimensional error.

Adopting the structure of the second aspect of the invention canincrease an area joined to the tube and a thermal contact area, thusallowing stronger joining between the corrugated fin and the tube andenhancing a heat dissipation effect of the corrugated fin.

Adopting the structure of the third aspect of the invention can avoidstress concentration on a bent part.

Adopting the structure of the fourth aspect of the invention can furtherincrease the rigidity of the flat plate section without fail and allowseasier and more reliable bending at the boundary between the flat platesection and the joining section.

The heat exchanger of the fifth aspect of the invention has increasedproduct accuracy and is thus easy to produce.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a general perspective view of a radiator in accordance with afirst exemplary embodiment of the present invention.

FIG. 2 is an enlarged perspective view of part. X in FIG. 1.

FIG. 3( a) illustrates the structure of a flat plate section viewed fromthe direction of arrow Y in FIG. 2, and FIGS. 3( b), 3(c) and 3(d) aresectional views taken along respective lines A-A, B-B, B′-B′ in FIG. 3(a).

FIG. 4 is an enlarged view of an essential part viewed from thedirection of arrow Z in FIG. 2.

FIG. 5( a) illustrates a method of manufacturing a corrugated fin, FIG.5( b) is a state view before corrugation, FIG. 5( c) is a state viewafter the corrugation, and FIGS. 5( d) and 5(e) illustrate respectiveshapes of an even surface, with FIG. 5( d) illustrating a plane surfaceand FIG. 5( e) illustrating a curved surface.

FIG. 6 illustrates variations of the corrugated fin in accordance withthe first embodiment.

FIG. 7( a) illustrates the structure of a flat plate section of acorrugated fin in accordance with a second exemplary embodiment, andFIGS. 7( b), 7(c) and 7(d) are sectional views taken along respectivelines C-C, D-D, D′-D′ in FIG. 7( a).

FIG. 8( a) illustrates the structure of a flat plate section of acorrugated fin in accordance with a third exemplary embodiment, andFIGS. 8( b), 8(c) and 8(d) are sectional views taken along respectivelines E-E, F-F, F′-F′ in FIG. 8( a).

FIG. 9( a) illustrates the structure of a flat plate section of acorrugated fin in accordance with a fourth exemplary embodiment, andFIGS. 9( b) and 9(c) are sectional views taken along respective linesG-G, H-H in FIG. 9( a).

FIG. 10( a) illustrates the structure of a flat plate section of acorrugated fin in accordance with a fifth exemplary embodiment, andFIGS. 10( b) and 10(c) are sectional views taken along respective linesH, J-J in FIG. 10( a).

FIG. 11( a) illustrates the structure of a flat plate section of acorrugated fin in accordance with a sixth exemplary embodiment, andFIGS. 11( b) and 11(c) are sectional views taken along respective linesK-K, L-L in FIG. 11( a).

FIG. 12( a) illustrates the structure of a flat plate section of acorrugated fin in accordance with a seventh exemplary embodiment, andFIGS. 12(b), 12(c), 12(d) and 12(e) are sectional views taken alongrespective lines M-M, M′-M′, N-N, N′-N′ in FIG. 12( a).

FIG. 13( a) illustrates the structure of a flat plate section of acorrugated fin in accordance with an eighth exemplary embodiment, andFIGS. 13( b) and 13(c) are sectional views taken along respective linesQ-Q, R-R in FIG. 13( a).

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

Concrete exemplary embodiments of a corrugated fin and a heat exchangerincluding the corrugated fin according to the present invention aredemonstrated hereinafter with reference to the accompanying drawings.The following description is provided of an example in which theinvention is applied to a radiator installed in an engine room of a workvehicle such as a hydraulic excavator or a bulldozer. However, it goeswithout saying that the invention is applicable to heat exchangershaving the same basic structure as the radiator, such as an oil coolerand an after-cooler.

First Exemplary Embodiment

FIG. 1 is a general perspective view of a radiator including acorrugated fin in accordance with the first, exemplary embodiment, ofthe invention.

(Description of a Schematic Structure of the Radiator)

Radiator 1 shown in FIG. 1 is a device for dissipating heat that enginecooling water (a heat exchange medium) circulating between radiator 1and an engine (not shown) obtains from the engine.

This radiator 1 is constructed mainly of top tank 2, bottom tank 3,tubes 4 and corrugated fins 5.

Top tank 2 and bottom tank 3 are coupled through the plurality of tubes4, thus allowing the engine cooling water coming from the engine to beonce stored in top tank 2, then pass through the plurality of tubes 4 tobe stored in bottom tank 3 and be returned to the engine thereafter.

Tubes 4 and corrugated fins 5 are alternately stacked to form radiatorcore 6.

(Description of the Tubes)

As shown in FIG. 2, tubes 4 are each formed of a flattened tube memberhaving internal passage 4 a for the engine cooling water.

The plurality of tubes 4 are arranged at predetermined pitch Pa alongwidth direction RW of radiator 1 and at predetermined spacing S alongdepth direction RD of radiator 1.

(Brief Description of the Corrugated Fin)

Corrugated fin 5 is disposed between tubes 4 which are adjacent in widthdirection RW of radiator 1. Corrugated fin 5 has flat plate sections 5 aand joining sections 5 b that are alternately formed into a corrugatedshape by bending.

(Brief Description of the Flat Plate Section)

Each flat plate section 5 a is a rectangular plate section having a pairof lateral sides 11, 11′ facing each other in width direction RW ofradiator 1 and a pair of end sides 12, 12′ facing each other in depthdirection RD of radiator 1.

(Description of Groove-Shaped Recesses of the Flat Plate Section)

As shown in FIG. 3( a), flat plate section 5 a is provided with, on itssurface, the plurality of groove-shaped recesses 13 regularly spaced atpredetermined pitch Pb along direction FD in which the pair of end sides12, 12′ are arranged.

Groove-shaped recesses 13 extend linearly in a direction from end side12 toward end side 12′ while slanting in a direction from lateral side11 toward lateral side 11′.

Pitch Pb for arranging groove-shaped recesses 13, an angle ofinclination, length and width of each groove-shaped recess 13 and othersare determined so that adjacent groove-shaped recesses 13 partly overlapeach other when viewed in direction FW in which the pair of lateralsides 11, 11′ are arranged. Providing the plurality of groove-shapedrecesses 13 on the surface of flat plate section 5 a causes a partbetween adjacent groove-shaped recesses 13 to become relativelystripe-shaped protrusion 14. In addition, providing groove-shapedrecesses 13 on the surface of flat plate section 5 a results information of corresponding stripe-shaped protrusions 15 (see FIGS. 3( b)and 3(c)) on a back surface of flat plate section 5 a.

(Description of Recesses and Protrusions of the Flat Plate Section inArbitrary Sections)

As shown in FIG. 3( b), flat plate section 5 a has the plurality ofrecesses 16 defined by the respective plurality of groove-shapedrecesses 13 in the arbitrary section taken along direction FD in whichthe pair of end sides 12, 12′ are arranged. In other words, flat platesection 5 a has the plurality of protrusions 17, 18 defined by therespective plurality of stripe-shaped protrusions 14, 15 in thearbitrary section taken along direction FD in which end sides 12, 12′are arranged.

As shown in FIGS. 3( c) and 3(d), flat plate section 5 a has recesses 16defined by respective groove-shaped recesses 13 in the arbitrarysections taken along direction FW in which the pair of lateral sides 11,11′ are arranged. In other words, flat plate section 5 a has protrusions17, 18 defined by respective stripe-shaped protrusions 14, 15 in thearbitrary sections taken along direction FW in which lateral sides 11,11′ are arranged. It is to be noted that there exists, as shown in FIG.3( c), one recess 16 defined by groove-shaped recess 13 or oneprotrusion 18 defined by stripe-shaped protrusion 15 in the section offlat plate section 5 a that is taken along line B-B, while there exists,as shown in FIG. 3( d), two recesses 16 defined by respectivegroove-shaped recesses 13 or two protrusions 18 defined by respectivestripe-shaped protrusions 15 in the section taken along line B′-B′.

(Brief Description of the Joining Section)

As shown in FIG. 4, joining section 5 b is a rectangular plate sectionwhich makes a right angle with flat plate section 5 a, is narrower thanflat plate section 5 a and has even surface 20 joined to tube 4. Evensurface 20 is a plane surface parallel to surface 21 of tube 4.

Conceptually, this even surface 20 has two implications, one of which isthat surface 20 is a completely even surface free of undulation and theother of which is that surface 20 is a substantially even surfacehaving, compared with groove-shaped recesses 13, extremely negligibleshallow grooves (grooved remnants) which are formed inevitably when agrooving process is carried out to form groove-shaped recesses 13 inflat plate section 5 a.

(Description of Joining between the Corrugated Fin and the Tube)

Corrugated fin 5 and tube 4 are joined together by brazing using brazingfiller metal 22 interposed between even surface 20 of joining section 5b and surface 21 of tube 4.

Because of being plane, even surface 20 of joining section 5 b can havea larger area joined to tube 4 and a larger thermal contact areacompared to cases where even surface 20 is a curved surface or anangular surface.

Obtaining the larger joining area between even surface 20 of joiningsection 5 b and surface 21 of tube 4 enables stronger joining betweencorrugated fin 5 and tube 4.

Obtaining the larger thermal contact area between even surface 20 ofjoining section 5 b and surface 21 of tube 4 enables efficientconduction of the heat of the engine cooling water, which flows throughtube 4, from tube 4 to corrugated fin 5, thereby enhancing a heatdissipation effect of corrugated fin 5.

(Description of a Method of Manufacturing the Corrugated Fin)

A description is provided next of the method of manufacturing corrugatedfin 5 with reference to FIG. 5( a).

The manufacturing method of corrugated fin 5 includes the groovingprocess and a corrugating process.

(Description of the Grooving Process)

The grooving process is a process of forming the plurality ofgroove-shaped recesses 13 on a surface of bandlike sheet 30 a, acorrugated fin material, by passing bandlike sheet 30 a uncoiled fromsheet coil 30 between a pair of first rollers 31, 31′.

The pair of first rollers 31, 31′ have a plurality of recesses andprotrusions (not shown) on their outer peripheral surfaces to correspondto the plurality of groove-shaped recesses 13 to he formed in bandlikesheet 30 a. As first rollers 31, 31′ are rotated in respectivedirections of arrows in the drawing, bandlike sheet 30 a is sandwichedbetween these rollers 31, 31′ and then sent downstream. Here, theplurality of groove-shaped recesses 13 are formed on the surface ofbandlike sheet 30 a as a result of bandlike sheet 30 a being sandwichedbetween the recesses of first roller 31 on one side and the protrusionsof first roller 31′ on the other side.

It is to be noted that similar groove-shaped recesses 13 can be formedon the surface of bandlike sheet 30 a by press working using a pressmachine.

(Description of the Corrugating Process)

The corrugating process is a bending process in which bandlike sheet 30a coming out from between the pair of first rollers 31, 31′ is passedthrough a pair of second rollers 32, 32′ disposed downstream of firstrollers 31, 31′, whereby flat plate sections 5 a and joining sections 5b form the corrugated shape in an alternating sequence.

The pair of second rollers 32, 32′ have a plurality of teeth (not shown)on their outer peripheral surfaces for bending bandlike sheet 30 a,which has groove-shaped recesses 13 formed on its surface, into thecorrugated shape. The teeth of roller 32 and the teeth of roller 32′ areformed to mesh together. As second rollers 32, 32′ are rotated inrespective directions of arrows in the drawing, bandlike sheet 30 a issandwiched between these rollers 32, 32′ and then sent downstream. Here,bandlike sheet 30 a is bent into the corrugated shape as a result ofbeing sandwiched between a space between the teeth of second roller 32and the tooth of second roller 32′.

As shown in FIG. 5( b), bandlike sheet 30 a which will undergo thecorrugation has sections (indicated by arrows T in the drawing) free ofgroove-shaped recesses 13 and stripe-shaped protrusions 14 resultingfrom groove-shaped recesses 13. The corrugation is carried out so thatthese sections become joining sections 5 b each having even surface 20(see FIG. 5( c)).

In this embodiment, even surface 20 is plane as shown in FIG. 5( d).However, even surface 20 is not limited to this and may also be curvedas shown in FIG. 5( e). Forming even surface 20 into the curved surfacecan avoid stress concentration on a bent part.

Corrugated fin 5 which has undergone the corrugating process is thussandwiched between adjacent tubes 4 and joined to those tubes 4 bybrazing.

Description of Effects of the First Embodiment

In corrugated fin 5 of the first embodiment, flat plate section 5 a isprovided with, as shown in FIGS. 3( b) and 3(c), recesses 16 defined bygroove-shaped recesses 13 or protrusions 17, 18 defined by stripe-shapedprotrusions 14, 15 in the arbitrary sections taken along the respectivetwo directions, that is, direction FW in which the pair of lateral sides11, 11′ are arranged and direction FD in which the pair of end sides 12,12′ are arranged. This can increase a section modulus of the sectiontaken along direction FD in which end sides 12, 12′ are arranged as wellas a section modulus of the section taken along direction FW in whichlateral sides 11, 11′ are arranged. For this reason, flat plate section5 a can have increased rigidity with respect to such a bending action asto bring lateral sides 11, 11′ close to each other as well as withrespect to such a bending action as to bring end sides 12, 12′ close toeach other.

Joining section 5 b is not provided with recess 16 defined bygroove-shaped recess 13 or protrusions 17, 18 defined by respectivestripe-shaped protrusions 14, 15 such as provided at flat plate section5 a. This allows a large difference in rigidity between flat platesection 5 a and joining section 5 b, thus enabling easy and reliablebending at a boundary between flat plate section 5 a and joining section5 b.

Consequently, bending at an unexpected place can be prevented withoutfail during the production of corrugated fin 5 or, more specifically, inthe corrugating process, thus reducing a dimensional error of corrugatedfin 5.

Radiator core 6 of radiator 1 of the first embodiment is assembled byalternately stacking tubes 4 and corrugated fins 5. Because thedimensional error of each corrugated fin 5 can be reduced, radiator core6 does not warp, thereby increasing product accuracy. Moreover, nocorrection of the dimensional error of corrugated fin 5 and no highskill for offsetting the dimensional errors against one another arerequired, thus facilitating the production.

Description of Variations of the First Embodiment

FIGS. 6( a) to 6(f) are plan views of respective flat plate sections 5a, illustrating the variations of corrugated fin 5 of the firstembodiment.

Corrugated fin 5 of the first embodiment has, at its flat plate section5 a, at least one recess 16 defined by groove-shaped recess 13 in thearbitrary section taken along each of the two directions, that is,direction FW in which the pair of lateral sides 11, 11′ are arranged anddirection FD in which the pair of end sides 12, 12 are arranged.Appropriate variations can be made on this structure without: departingfrom the spirit of this structure.

For example, groove-shaped recess 13 can be replaced by groove-shapedrecess 13A having a greater groove width than recess 13 as shown in FIG.6( a).

As shown in FIG. 6( b), pitch Pb at which groove-shaped recesses 13 arearranged can be changed to smaller pitch Pc.

As shown in FIG. 6( c), groove-shaped recesses 13 can be arranged atleast two different pitches Pd, Pe.

As shown in FIG. 6( d), groove-shaped recesses 13, 13A of differentgroove widths can be alternately arranged.

As shown in FIG. 6( e), a plurality of groove-shaped recesses 13Bshorter in length than groove-shaped recesses 13 are arrangedalternately as equivalents of recesses 13.

While groove-shaped recesses 13 extend linearly in the direction fromend side 12 of flat plate section 5 a toward end side 12′, slanting inthe direction from lateral side 11 toward lateral side 11′,groove-shaped recesses 13C shown in FIG. 6( f) can be adopted instead.These recesses 13C extend linearly in the direction from end side 12 offlat plate section 5 a toward end side 12′ while slanting in an oppositedirection, that is, from lateral side 11′ toward lateral side 11.

Second Through Eighth Exemplary Embodiments

Hereinafter, descriptions of corrugated fins 5A to 5G in accordance withthe respective second through eighth exemplary embodiments of thepresent invention are provided one by one. In the following embodiments,elements similar to those in the first embodiment have the samereference marks in drawings, the detailed descriptions of those elementsare omitted, and emphasis is placed on different features not seen inthe first embodiment.

Description of Groove-Shaped Recesses of a Flat Plate Section Shown inFIG. 7(a) in Accordance with the Second Embodiment

As shown in FIG. 7( a), corrugated fin 5.A of the second embodiment has,on a surface of its flat plate section 5 a, the plurality ofgroove-shaped recesses 40 regularly spaced at predetermined pitch Pfalong direction FD in which a pair of end sides 12, 12′ are arranged.

Each groove-shaped recess 40 is formed of first groove-shaped recess 40a and second groove-shaped recess 40 b, and in the plan view with endside 12′ of flat plate section 5 a being above the other end side 12,first and second groove-shaped recesses 40 a, 40 b connect in a V shape.

Starting from a middle point of direction FW in which a pair of lateralsides 11, 11′ of flat plate section 5 a are arranged, firstgroove-shaped recess 40 a extends linearly in a direction from end side12 toward end side 12′ while slanting in a direction from lateral side11 toward lateral side 11′.

Starting from the middle point of direction FW in which lateral sides11, 11′ of flat plate section 5 a are arranged, second groove-shapedrecess 40 b extends linearly in the direction from end side 12 towardend side 12′ while slanting in a direction from lateral side 11′ towardlateral side 11.

Description of Recesses and Protrusions of the Flat Plate Section inArbitrary Sections Shown in FIGS. 7(b), 7(c) and 7(d) in Accordance Withthe Second Embodiment

As shown in FIG. 7( b), flat plate section 5 a has the plurality ofrecesses 41 defined by the respective plurality of groove-shapedrecesses 40 in the arbitrary section taken along direction FD in whichthe pair of end sides 12, 12′ are arranged. In other words, flat platesection 5 a has the plurality of protrusions 44, 45 defined by arespective plurality of stripe-shaped protrusions 42, 43 in thearbitrary section taken along direction FD in which end sides 12, 12′are arranged.

As shown in FIGS. 7( c) and 7(d), flat plate section 5 a has recesses 41defined by groove-shaped recesses 40 in the arbitrary sections takenalong direction FW in which the pair of lateral sides 11, 11′ arearranged. In other words, flat plate section 5 a has protrusions 44, 45defined by stripe-shaped protrusions 42, 43 in the arbitrary sectionstaken along direction FW in which lateral sides 11, 11′ are arranged. Itis to be noted that there exists, as shown in FIG. 7( c), one recess 41defined by groove-shaped recess 40 or one protrusion 45 defined bystripe-shaped protrusion 43 in the section of flat plate section 5 athat is taken along line D-D, while there exists, as shown in FIG. 7(d), two recesses 41 defined by groove-shaped recess 40 or twoprotrusions 45 defined by stripe-shaped protrusion 43 in the sectiontaken along line D′-D′.

Description of Groove-Shaped Recesses of a Flat Plate Section Shown inFIG. 8(a) in Accordance With the Third Embodiment

As shown in FIG. 8( a), corrugated fin 5B of the third embodiment has,on a surface of its flat plate section 5 a, the plurality ofgroove-shaped recesses 46 regularly spaced at predetermined pitch Pgalong direction FD in which a pair of end sides 12, 12′ are arranged.

Groove-shaped recesses 46 are recesses each bent into an arc shape,bulging toward end side 12 between lateral sides 11, 11′.

Description of Recesses and Protrusions of the Flat Plate Section inArbitrary Sections Shown in FIGS. 8(b), 8(c) and 8(d) in Accordance Withthe Third Embodiment

As shown in FIG. 8( b), flat plate section 5 a has the plurality ofrecesses 47 defined by the respective plurality of groove-shapedrecesses 46 in the arbitrary section taken along direction FD in whichthe pair of end sides 12, 12′ are arranged. In other words, flat platesection 5 a has the plurality of protrusions 50, 51 defined by arespective plurality of stripe-shaped protrusions 48, 49 in thearbitrary section taken along direction FD in which end sides 12, 12′are arranged.

As shown in FIGS. 8( c) and 8(d), flat plate section 5 a has recesses 47defined by groove-shaped recesses 46 in the arbitrary sections takenalong direction FW in which the pair of lateral sides 11, 11′ arearranged. In other words, flat plate section 5 a has protrusions 50, 51defined by stripe-shaped protrusions 48, 49 in the arbitrary sectionstaken along direction FW in which lateral sides 11, 11′ are arranged. Itis to be noted that there exists, as shown in FIG. 8( c), one recess 47defined by groove-shaped recess 46 or one protrusion 51 defined bystripe-shaped protrusion 49 in the section of flat plate section 5 athat is taken along line F-F, while there exists, as shown in FIG. 8(d), two recesses 47 defined by groove-shaped recess 46 or twoprotrusions 51 defined by stripe-shaped protrusion 49 in the sectiontaken along line F′-F′.

Description of Groove-Shaped Recesses of a Flat Plate Section Shown inFIG. 9(a) in Accordance With the Fourth Embodiment

As shown in FIG. 9( a), corrugated fin 5C of the fourth embodiment has,on a surface of its flat plate section 5 a, the plurality ofgroove-shaped recesses 52 regularly spaced at predetermined pitch Phalong direction FD in which a pair of end sides 12, 12′ are arranged.

Each groove-shaped recess 52 is formed of first groove-shaped recess 52a, second groove-shaped recess 52 b, third groove-shaped recess 52 c andfourth groove-shaped recess 52 d, and in the plan view with end side 12′of flat plate section 5 a being above the other end side 12, those firstthrough fourth groove-shaped recesses 52 a, 52 b, 52 c, 52 d connect ina W shape.

Starting from a point located in the middle between lateral side 11′ anda middle point of direction FW in which lateral sides 11, 11′ of flatplate section 5 a are arranged, first groove-shaped recess 52 a extendslinearly in a direction from end side 12 toward end side 12′ whileslanting in a direction from lateral side 11 toward lateral side 11′.

Starting from the point located in the middle between lateral side 11′and the middle point of direction FW in which lateral sides 11, of flatplate section 5 a are arranged, second groove-shaped recess 52 b extendslinearly in the direction from end side 12 toward end side 12′ whileslanting in a direction from lateral side 11′ toward lateral side 11.

Starting from a point located in the middle between lateral side 11 andthe middle point of direction FW in which lateral sides 11, 11′ of flatplate section 5 a are arranged, third groove-shaped recess 52c extendslinearly in the direction from end side 12 toward end side 12′ whileslanting in the direction from lateral side 11 toward lateral side 11′.

Starting from the point located in the middle between lateral side 11and the middle point of direction FW in which lateral sides 11, 11′ offlat plate section 5 a are arranged, fourth groove-shaped recess 52 dextends linearly in the direction from end side 12 toward end side 12′while slanting in the direction from lateral side 11′ toward lateralside 11.

Description of Recesses and Protrusions of the Flat Plate Section inArbitrary Sections Shown in FIGS. 9(b) and 9(c) in Accordance With theFourth Embodiment

As shown in FIG. 9( b), flat plate section 5 a has the plurality ofrecesses 53 defined by the respective plurality of groove-shapedrecesses 52 in the arbitrary section taken along direction FD in whichthe pair of end sides 12, 12′ are arranged. In other words, flat platesection 5 a has the plurality of protrusions 56, 57 defined by arespective plurality of stripe-shaped protrusions 54, 55 in thearbitrary section taken along direction FD in which end sides 12, 12′are arranged.

As shown in FIG. 9( c), flat plate section 5 a has at least two recesses53 defined by groove-shaped recess 52 in the arbitrary section takenalong direction FW in which the pair of lateral sides 11, 11′ arearranged. In other words, flat plate section 5 a has at least twoprotrusions 56, 57 defined by stripe-shaped protrusion 54, 55 in thearbitrary section taken along direction FW in which lateral sides 11,11′ are arranged.

Description of Groove-Shaped Recesses of a Flat Plate Section Shown inFIG. 10(a) in Accordance With the Fifth Embodiment

As shown in FIG. 10( a), corrugated fin 5D of the fifth embodiment has,on a surface of its flat plate section 5 a, the plurality ofgroove-shaped recesses 58 regularly spaced at predetermined pitch Pialong direction FW in which a pair of lateral sides 11, 11′ arearranged.

Each groove-shaped recess 58 is formed of first groove-shaped recess 58a, second groove-shaped recess 58 b, third groove-shaped recess 58 c andfourth groove-shaped recess 58 d, and in the plan view with lateral side11′ of flat plate section 5 a being above the other lateral side 11,those first through fourth groove-shaped recesses 58 a, 58 b, 58 c, 58 dconnect in an M shape.

Starting from a point located in the middle between end side 12 and amiddle point of direction FD in which a pair of end sides 12, 12′ offlat plate section 5 a are arranged, first groove-shaped recess 58 aextends linearly in a direction from end side 12′ toward end side 12while slanting in a direction from lateral side 11′ toward lateral side11.

Starting from the point located in the middle between end side 12 andthe middle point of direction FD in which end sides 12, 12′ of flatplate section 5 a are arranged, second groove-shaped recess 58 b extendslinearly in a direction from end side 12 toward end side 12′ whileslanting in the direction from lateral side 11′ toward lateral side 11.

Starting from a point located in the middle between end side 12′ and themiddle point of direction FD in which lateral sides 12, 12′ of flatplate section 5 a are arranged, third groove-shaped recess 58 c extendslinearly in the direction from end side 12′ toward end side 12 whileslanting in the direction from lateral side 11′ toward lateral side 11.

Starting from the point located in the middle between end side 12′ andthe middle point of direction FD in which lateral sides 12, 12′ of flatplate section 5 a are arranged, fourth groove-shaped recess 58 d extendslinearly in the direction from end side 12 toward end side 12′ whileslanting in the direction from lateral side 11′ toward lateral side 11.

Description of Recesses and Protrusions of the Flat Plate Section inArbitrary Sections Shown in FIGS. 10(b) and 10(c) in Accordance With theFifth Embodiment

As shown in FIG. 10( b), flat plate section 5 a has at least tworecesses 59 defined by groove-shaped recesses 58 in the arbitrarysection taken along direction FD in which the pair of end sides 12, 12′are arranged. In other words, flat plate section 5 a has at least twoprotrusions 62, 63 defined by stripe-shaped protrusions 60, 61 in thearbitrary section taken along direction FD in which end sides 12, 12′are arranged.

As shown in FIG. 10( c), flat plate section 5 a has the plurality ofrecesses 59 defined by the respective plurality of groove-shapedrecesses 58 in the arbitrary section taken along direction FW in whichthe pair of lateral sides 11, 11′ are arranged. In other words, flatplate section 5 a has the plurality of protrusions 62, 63 defined by therespective plurality of stripe-shaped protrusions 60, 61 in thearbitrary section taken along direction FW in which lateral sides 11,11′ are arranged.

Description of Groove-Shaped Recesses of a Flat Plate Section Shown inFIG. 11(a) in Accordance With the Sixth Embodiment

As shown in FIG. 11( a), corrugated fin 5E of the sixth embodiment has,on a surface of its flat plate section 5 a, the plurality of firstgroove-shaped recesses 64 and the plurality of second groove-shapedrecesses 65 that are regularly spaced at predetermined pitch Pj alongdirection FD in which a pair of end sides 12, 12′ are arranged.

Each first groove-shaped recess 64 extends linearly in a direction fromend side 12 toward end side 12′ while slanting in a direction fromlateral side 11 toward lateral side 11′.

Each second groove-shaped recess 65 extends linearly in the directionfrom end side 12 toward end side 12′ while slanting in a direction fromlateral side 11′ toward lateral side 11.

First groove-shaped recesses 64 cross second groove-shaped recesses 65,thus forming a mesh-like pattern as a whole.

Description of Recesses and Protrusions of the Flat Plate Section inArbitrary Sections Shown in FIGS. 11(b) and 11(c) in Accordance With theSixth Embodiment

As shown in FIG. 11( b), flat plate section 5 a has the plurality ofrecesses 66 defined by the plurality of groove-shaped recesses 64, 65 inthe arbitrary section taken along direction FD in which the pair of endsides 12, 12′ are arranged. In other words, flat plate section 5 a hasthe plurality of protrusions 69, 70 defined by a plurality ofstripe-shaped protrusions 67, 68 in the arbitrary section taken alongdirection FD in which end sides 12, 12′ are arranged.

As shown in FIG. 11( c), flat plate section 5 a has the plurality ofrecesses 66 defined by the plurality of groove-shaped recesses 64, 65 inthe arbitrary section taken along direction FW in which the pair oflateral sides 11, 11′ are arranged. In other words, flat plate section 5a has the plurality of protrusions 69, 70 defined by the plurality ofstriped-shaped protrusions 67, 68 in the arbitrary section taken alongdirection FW in which lateral sides 11, 11′ are arranged.

Description of Groove-Shaped Recesses of a Flat Plate Section Shown inFIG. 12(a) in Accordance With the Seventh Embodiment

As shown in FIG. 12( a), corrugated fin 5F of the seventh embodiment hasfirst groove-shaped recess 71 and second groove-shaped recess 72 on asurface of its flat plate section 5 a.

First groove-shaped recess 71 extends linearly between a corner wherelateral side 11 and end side 12 meet and a corner where lateral side 11′and end side 12′ meet.

Second groove-shaped recess 72 extends linearly between a corner wherelateral side 11′ and end side 12 meet and a corner where lateral side 11and end side 12′ meet.

First groove-shaped recess 71 and second groove-shaped recess 72 crosseach other, thus forming an X shape.

Description of Recesses and Protrusions of the Flat Plate Section inArbitrary Sections Shown in FIGS. 12(b), 12(c), 12(d) and 12(e) inAccordance With the Seventh Embodiment

As shown in FIGS. 12( b) and 12(c), flat plate section 5 a has recesses73, 74 defined by groove-shaped recesses 71, 72 in the arbitrarysections taken along direction FD in which the pair of end sides 12, 12′are arranged. In other words, flat plate section 5 a has protrusions 77,78 defined by stripe-shaped protrusions 75, 76 in the arbitrary sectionstaken along direction FD in which end sides 12, 12′ are arranged. It isto be noted that there exists, as shown in FIG. 12( b), one recess 73(74) defined by groove-shaped recess 71 (72) or one protrusion 77 (78)defined by stripe-shaped protrusion 75 (76) in the section of flat platesection 5 a that is taken along line M-M, while there exists, as shownin FIG. 12( c), two recesses 73 (74) defined by respective groove-shapedrecesses 71 (72) or two protrusions 77 (78) defined by respectivestripe-shaped protrusions 75 (76) in the section taken along line M′-M′.

As shown in FIGS. 12( d) and 12(e), flat plate section 5 a has recessesdefined by groove-shaped recesses 71, 72 in the arbitrary sections takenalong direction FW in which the pair of lateral sides 11, 11′ arearranged. In other words, flat plate section has protrusions 77, 78defined by stripe-shaped protrusions 75, 76 in the arbitrary sectionstaken along direction FW in which lateral sides 11, 11′ are arranged. Itis to be noted that there exists, as shown in FIG. 12( d), one recess 73(74) defined by groove-shaped recess 71 (72) or one protrusion 77 (78)defined by stripe-shaped protrusion 75 (76) in the section of flat platesection 5 a that is taken along line N-N, while there exists, as shownin FIG. 12( e), two recesses 73 (74) defined by respective groove-shapedrecesses 71 (72) or two protrusions 77 (78) defined by respectivestripe-shaped protrusions 75 (76) in the section taken along line N′-N′.

Description of Groove-Shaped Recesses of a Flat Plate Section Shown inFIG. 13(a) in Accordance With the Eighth Embodiment

As shown in FIG. 13( a), corrugated fin 5G of the eighth embodiment has,on a surface of its flat plate section 5 a, the plurality of hemisphericrecesses 79 in a staggered arrangement in direction FW in which a pairof lateral sides 11, 11′ are arranged as well as in direction FD inwhich a pair of end sides 12, 12′ are arranged.

Pitch Pk for arranging hemispheric recesses 79, a diameter of eachhemispheric recess 79 and others are determined so that hemisphericrecesses 79 adjacent in direction FD in which end sides 12, 12′ arearranged partly overlap each other when viewed in direction FW in whichlateral sides 11, 11′ are arranged.

Pitch Pm for arranging hemispheric recesses 79, the diameter of eachhemispheric recess 79 and others are determined so that hemisphericrecesses 79 adjacent in direction FW in which lateral sides 11, 11′ arearranged partly overlap each other when viewed in direction FD in whichend sides 12, 12′ are arranged.

Description of Recesses and Protrusions of the Flat Plate Section inArbitrary Sections Shown in FIGS. 13(b) and 13(c) in Accordance With theEighth Embodiment

As shown in FIG. 13( b), flat plate section 5 a has the plurality ofrecesses 80 defined by the respective plurality of hemispheric recesses79 in the arbitrary section taken along direction FD in which the pairof end sides 12, 12′ are arranged. In other words, flat plate section 5a has the plurality of protrusions 82 defined by a respective pluralityof hemispheric protrusions 81 in the arbitrary section taken alongdirection FD in which end sides 12, 12′ are arranged.

As shown in FIG. 13( c), flat plate section 5 a has the plurality ofrecesses 80 defined by the respective plurality of hemispheric recesses79 in the arbitrary section taken along direction FW in which the pairof lateral sides 11, 11′ are arranged. In other words, flat platesection 5 a has the plurality of protrusions 82 defined by therespective plurality of hemispheric protrusions 81 in the arbitrarysection taken along direction FW in which lateral sides 11, 11′ arearranged.

Description of Effects of the Second through Eighth Embodiments

Even in each of corrugated fins 5A, 5B, 5C, 5D, 5E, 5F, 5G of the secondthrough eighth embodiments, flat plate section 5 a is provided with atleast one recess 41, 47, 53, 59, 66, 73 or 74 defined by groove-shapedrecess 40, 46, 52, 58, 64, 65, 71 or 72 or at least one protrusion 44,45, 50, 51, 56, 57, 62, 63, 69, 70, 77 or 78 defined by stripe-shapedprotrusion 42, 43, 48, 49, 54, 55, 60, 61, 67, 68, 75 or 76, or at leastone recess 80 defined by hemispheric recess 79 or at least oneprotrusion 82 defined by hemispheric protrusion 81 in the arbitrarysection taken along each of the two directions, that is, direction FW inwhich the pair of lateral sides 11, 11′ are arranged and direction FD inwhich the pair of end sides 12, 12′ are arranged. This can increase asection modulus of the section taken along direction FD in which endsides 12, 12′ are arranged as well as a section modulus of the sectiontaken along direction FW in which lateral sides 11, 11′ are arranged.Therefore, corrugated fins 5A to 5G of the second through eighthembodiments can provide the same effects as corrugated fin 5 of thefirst embodiment. Similarly to radiator 1 of the first embodiment,radiators including such respective corrugated fins 5A to 5G haveincreased product accuracy, thus facilitating their production.

The embodiments and variations of the corrugated fin and the heatexchanger including the corrugated fin according to the presentinvention have been described above. However, the present invention isnot limited to the structures described in the above embodiments andvariations and allows appropriate variations on each of the structureswithout departing from the spirit of the invention, such as,appropriately combining the structures of the above-describedembodiments and variations.

INDUSTRIAL APPLICABILITY

A corrugated fin and a heat exchanger including the corrugated finaccording to the present invention have the characteristic of beingcapable of reliably preventing bending at an unexpected place duringproduction, thereby improving product accuracy and facilitating theproduction, and therefore, are suitable for use in and as a radiator, anoil cooler, an after-cooler or the like.

DESCRIPTION OF REFERENCE MARKS IN THE DRAWINGS

1 radiator (heat exchanger)

4 tube

5, 5A, 5B, 5C, 5D, 5E, 5F, 5G corrugated fins

5 a flat plate section

5 b joining section

11, 11′ lateral sides

12, 12′ end sides groove-shaped recess (first embodiment)

13A groove-shaped recess (variation of first embodiment)

13B groove-shaped recess (variation of first embodiment) groove-shapedprotrusion (first embodiment)

16 recess (first embodiment)

17, 18 protrusions (first embodiment)

20 even surface

40 groove-shaped recess (second embodiment)

41 recess (second embodiment)

42, 43 stripe-shaped protrusions (second embodiment)

44, 45 protrusions (second embodiment)

46 groove-shaped recess (third embodiment)

47 recess (third embodiment)

49, 48 stripe-shaped protrusions (third embodiment)

50, 51 protrusions (third embodiment)

52 groove-shaped recess (fourth embodiment)

53 recess (fourth embodiment)

54, 55 stripe-shaped protrusions (fourth embodiment)

56, 57 protrusions (fourth embodiment)

58 groove-shaped recess (fifth embodiment)

59 recess (fifth embodiment)

60, 61 stripe-shaped protrusions (fifth embodiment)

62, 63 protrusions (fifth embodiment)

64, 65 groove-shaped recesses (sixth embodiment)

66 recess (sixth embodiment)

67, 68 stripe-shaped protrusions (sixth embodiment)

69, 70 protrusions (sixth embodiment)

71, 72 stripe-shaped recesses (seventh embodiment)

73, 74 recesses (seventh embodiment)

75, 76 stripe-shaped protrusions (seventh embodiment)

77, 78 protrusions (seventh embodiment)

79 hemispheric recess (eighth embodiment)

80 recess (eighth embodiment)

81 hemispheric protrusion (eighth embodiment)

82 protrusion (eighth embodiment)

1. A corrugated fin for a heat exchanger, comprising: a flat platesection and a joining section which are alternately formed into acorrugated shape by bending, said flat plate section having a pair oflateral sides facing each other and a pair of end sides facing eachother, said joining section connecting with a lateral side of the pairof lateral sides of the flat plate section, wherein said joining sectionhas an even surface joined to a tube through which a heat exchangemedium is circulated, and wherein said flat plate section has at leastone recess or protrusion in an arbitrary section taken in twodirections, one of the two directions being a direction in which thepair of lateral sides are arranged, and the other of the two directionsbeing a direction in which the pair of end sides are arranged.
 2. Thecorrugated fin of claim 1, wherein the even surface of the joiningsection is formed into a plane surface.
 3. The corrugated fin of claim1, wherein the even surface of the joining section is formed into acurved surface.
 4. The corrugated fin of claim 1, wherein two or morerecesses or protrusions are provided.
 5. A heat exchanger including thecorrugated fin of claim
 1. 6. The corrugated fin of claim 2, wherein twoor more recesses or protrusions are provided.
 7. The corrugated fin ofclaim 3, wherein two or more recesses or protrusions are provided.
 8. Aheat exchanger including the corrugated fin of claim
 2. 9. A heatexchanger including the corrugated fin of claim
 3. 10. A heat exchangerincluding the corrugated fin of claim
 4. 11. A heat exchanger includingthe corrugated fin of claim
 6. 12. A heat exchanger including thecorrugated fin of claim. 7.